Theoretical study on the detailed excited state triple proton transfer mechanism of cyclic 6-Azaindole trimer

Abstract The proton transfer mechanism of 6AI trimer in cyclohexane has been theoretical study by time-dependent density functional theoretical methods. After three 6AI monomers are connected to form trimer by hydrogen bonds, the calculated absorption spectra confirm that the experimental absorption peaks of 6AI monomer (about 280nm) and 6AI trimer (310nm) are attributed to the 6AI trimer and TPT tautomer respectively. Through the potential energy curves and the potential energy surface, it can be concluded that the 6AI trimer reaches the TPT tautomer in the S1 state through the concerted mechanism rather than the stepwise mechanism.